cancel my contract immediate

I upgrade online on 15 June 2020, I received a faulty device from vodacom. After many call they came to collect the faulty device on 26 August 2020. They told me today that the upgrade will be reversed on 1 October 2020 on which I can choose a new phone. I am not interested in doing business with Vodacom any longer. I want to cancel my contract with immediate effect and will take my number and go to another service provider that wants to help their clients and deliver excellent service. After 20 years of being with Vodacom, I expect better service.